Epidemiology of penicillin resistance in Streptococcus pneumoniae isolates in eastern France

Genetic relatedness, antibiotic susceptibility, and serotype distribution of Streptococcus pneumoniae responsible for meningitis in Poland, 1997-2001

Streptococcus pneumoniae is the third most frequent etiologic agent of bacterial meningitis in Poland. Therefore, the objective of this study was to characterize S. pneumoniae isolates responsible for meningitis in Poland from 1997 to 2001 by determining their serotypes, antimicrobial susceptibility, and genetic relatedness. Among 36 serotypes and rough isolates, the most common were serotypes 3, 8, 19F, 6B, 4, and 23F, altogether accounting for 45.3% of cases. Penicillin-nonsusceptible pneumococci constituted 14.8% of all isolates. A high heterogeneity of pneumococcal isolates concerning serological features as well as genetic relatedness based on pulsed-field gel electrophoresis analysis was observed. With the exception of some serotypes (e.g., 3, 7F, 19F), isolates of the same serotype do not appear to be more closely related to each other than to isolates of different serotypes.

Emergence of penicillin-nonsusceptible Streptococcus pneumoniae invasive clones in Canada

Distinctive international clones of penicillin-nonsusceptible and multidrug-resistant Streptococcus pneumoniae are increasingly being reported. We investigated the spread of these clones in Canada through an active surveillance that was carried out at 11 Canadian pediatric tertiary care centers from 1991 to 1998. All penicillin-nonsusceptible isolates were serotyped, tested for antibiotic susceptibility, and genotyped by pulsed-field gel electrophoresis (PFGE) and random amplified polymorphic DNA (RAPD). Forty-five penicillin-nonsusceptible S. pneumoniae isolates were evaluated. Eleven serotype 9V isolates and six serotype 14 isolates displayed identical RAPD and PFGE fingerprint profiles. Twelve (70%) of these isolates were encountered in Quebec. The 9V/14 clone and the Spanish-French clone had similar PFGE fingerprint patterns. Eight isolates of serotype 23F and two isolates of serogroup 14 had the same fingerprint profiles and displayed resistance to three or more antibiotic drug classes. This clone was first detected in Calgary (Alberta) and in 1996 appeared simultaneously in various regions of Canada. This clone showed a PFGE fingerprint pattern similar to that of the Spanish-U.S. 23F clone. Our data show the emergence across Canada of two international clones of penicillin-nonsusceptible S. pneumoniae: (i) serotypes 9V and 14 related to the Spanish-French clone and (ii) the 23F Spanish-U.S. clone. The source of the first clone was in Quebec and the second international clone was probably originated from the United States. The exact reasons for the successful spread of these clones within Canada and their contribution to increased resistance to antibiotics have yet to be explored.

Epidemiology of penicillin resistance in Streptococcus pneumoniae isolates in Kayseri, Turkey

OBJECTIVE

To determine the penicillin resistance and serotype distribution of Streptococcus pneumoniae strains and to identify clonal relationships of isolates resistant to penicillin by means of pulsed-field gel electrophoresis (PFGE).

METHODS

In total, 193 S. pneumoniae strains were isolated from clinical specimens between November 1997 and January 2000. Susceptibility testing was carried out by E test, and serotyping by the Quellung reaction. Clonal relationship was analyzed by using PFGE with smaI endonuclease.

RESULTS

Of the S. pneumoniae isolates, 23% were intermediately resistant to penicillin. There were no high-level resistant pneumococci. The majority of isolates intermediately resistant to penicillin were of serogroups/serotypes 19, 23, 14 and 1, in descending order of frequency. There were eight major clones in strains intermediately resistant to penicillin. It was seen that serogroups in the 23-valent polysaccharide vaccine, 7-valent, 9-valent, and 11-valent vaccine formulations caused 92%, 75%, 78% and 87% of pneumococcal diseases in our region, respectively.

CONCLUSION

Penicillin resistance in S. pneumoniae is relatively uncommon in Kayseri. All vaccine formulations can prevent the majority of pneumococcal diseases, and there is genetic heterogeneity in intermediately penicillin-resistant pneumococci in this region.

Antibiotic susceptibility and serotype distribution of Streptococcus pneumoniae causing meningitis in Italy, 1997-1999

Because few data are available in Italy regarding antimicrobial susceptibility and serotype distribution of invasive Streptococcus pneumoniae strains, meningeal isolates collected at Italian hospitals during the years 1997-1999 were studied. The 12 most common serogroups, representing > 85% of the isolates, were 14, 23, 6, 4, 3, 9, 19, 8, 1, 12, 18, and 7 (in order of frequency). The serogroups identified in children < 5 years old were more limited in number: 80% are included in the 7-valent conjugate vaccines. Penicillin resistance was observed in 14 (9.5%) of 148 strains and increased from 5% in the first part of the study to 13% in the last part. Only 2 strains were fully penicillin resistant, and these belonged to serotype 9V. Thirty percent of the strains, mostly belonging to serogroups 14 or 6 and carrying either the ermB or the mef genes, were resistant to erythromycin.

Antibiotic susceptibility and genotypic characterization of Haemophilus influenzae strains isolated from nasopharyngeal specimens from children in day-care centers in eastern France

OBJECTIVE

To determine the overall carriage rate for Haemophilus influenzae in young children in day-care centers, the frequency of resistance to various classes of antibiotic, and the clonal relationship between isolates of the various resistant phenotypes.

METHODS

Nasopharyngeal (NP) specimens were obtained and cultured on chocolate agar with bacitracin. Antibiotic susceptibility testing and serotyping were performed for all isolates. The genetic polymorphism of ampicillin-susceptible and beta-lactamase-producing isolates was studied by pulsed-field gel electrophoresis using SmaI.

RESULTS

Of the 596 NP secretion cultures, 152 (25.5%) were positive for H. influenzae. Sixty-four (42.1%) isolates produced beta-lactamase and two (1.3%) were ampicillin resistant but did not produce beta-lactamase. We were unable to serotype 150 isolates; one isolate belonged to capsular serotype e and one to serotype f. Forty-six major DNA patterns were identified among 76 randomized isolates. beta-lactamase producing isolates more frequently showed EP than ampicillin-susceptible isolates P < 10(-4). The frequency of isolates with EP was significantly lower in day-care centers attended by less than 20 children than in those attended by more than 20 children (P = 0.020).

CONCLUSIONS

Resistance due to beta-lactamase production has disseminated in some day-care centers, mostly by person-to-person spread but also via the possible conjugal transfer of large plasmids between strains. The size of day-care centers may affect the risk of transmission.